6 Mar
2009
6 Mar
'09
7:36 a.m.
>>>> "Keith" == Keith
<keithvz at verizon.net> writes:
Keith> Alexandre Souza wrote:
>> I've seriously contemplated making my own
matching memory
>> expansion module for my VXL/30 A500 cpu accelerator. Fairly
>> complicated because I have to create a DRAM controller. Thinking
>> FGPA w/ a pre-made memory controller core.
> Something I could never understand: Why not using SRAM?
Keith> Alexandre,
Keith> I haven't ruled out SRAM. As a matter of fact, it was my
Keith> first choice. It just seems like SRAM (and memory in general)
Keith> is somewhat hard to buy new in the right form factor and in
Keith> low quantities.
What is "right formfactor"?
Keith> I'd prefer something that is wide, 32-bits, or I could use two
Keith> 16's. And I need 8mb. And it needs to be fast. The memory
Keith> would need to be faster than 60ns. I'll be losing time
Keith> through the fpga, so faster memory is definitely a plus.
Keith> I've looked at digikey, mouser, newark, and I can't seem to
Keith> find memory that fits the bill.
8 Mbit or 8 MByte? Digikey mentions Cypress sync SRAM, 512k by 36,
that' 18 Mbit, $30 quantity 1. Or 256k by 36 (9 Mbit), $16 quantity
one. Those are TQFP-100 packages, which are easy enough to
hand-solder if you're careful and a good magnifying glass, fine tip
iron, and thin solder.
As I recall, several of the FPGA eval boards (Xilinx Virtex, for one)
come with sync SRAM.
paul